电加热管的热传递介质----氧化镁的有关知识

 电加热管和电热丝之间需要绝缘和导热性能非常好的填充料来传递热量，并与电热丝要有相近的线胀系数，还要耐热性、耐震性好，在常温和高温时均不与电加热丝或管子发生化学作用。最好没有吸湿性或吸湿度极低，能承受剧烈的变化，机械强度要高，而且要价廉易得。通常有氧化镁、苛性镁、氧化铝和洁净的石英砂等填充料（性能从好到差），一般顾客没有特殊要求我们都选用性能相对较好的氧化镁。●性能要求1.MｇO粉在工作温度的时候，其要具有较高的导热性能，以便能迅速地把热量传递到管表面上去，使电阻丝与管壁温度更接近；2.当工作温度在1100℃之内时，MｇO粉应具有较好的绝缘性能；3.MｇO粉必须具有一定的颗粒度，形状一般是圆状而不是我国目前生产的片状，因为圆状的灌粉密度大，电加热棒流动性好，且具有一定颗粒的百分比含量，加粉时不易损坏发热丝，保证毫无困难地进行灌粉；4.MｇO粉无论在常温或高温的情况下对发热丝材料和管材应无腐蚀的现象。5.氧化镁粉的吸水率不得高于下列规定：　1）、普通型                  ≤1.5％2）、低温防潮型           ≤0.05％3）、中温防潮型           ≤0.10％4）、高温型                  ≤0.10％ 今天小编就给大家讲解一下电加热管的热传递介质--氧化镁的性能要求，大家可以好好学习一下

Need insulation between the heating wire and electric heating tube and heat conduction performance is very good filling material to transfer heat, and the heating wire should have similar linear expansion coefficient, heat resistance, good shock resistance, even at normal temperature and high temperature are not chemistry with the electric heating wire or pipe. Had better not hygroscopic or very low moisture absorption, can withstand the dramatic changes, higher mechanical strength, but also cheap. Usually has a magnesium oxide, caustic magnesium, aluminum oxide and clean quartz sand filling material (performance from good to bad), generally no special customer requirements we all choose a relatively good performance of magnesium oxide. Low performance requirements 1. MgO style powder at the time of working temperature, it will have high thermal conductivity, so that they can quickly to the heat transfer to the tube surface, make the resistance wire and tube wall temperature is closer to; 2. When within the working temperature at 1100 ℃, MgO style powder should be has good insulating performance; 3. MgO style powder must have a certain granularity, shape is generally cone instead of the current production of sheet, because the cone filling powder density is big, good liquidity, and has a certain particle percentage content, add powder is not easy to damage the heating wire, ensure filling powder have no difficulty (in); 4. Under the condition of MgO style powder in room temperature or high temperature of heat wire material and pipe should be no corrosion phenomenon. 5. Magnesium oxide powder bibulous rate shall not be higher than the following provisions: 1), 2) normal 1.5% or less, low moisture 0.05% or less (3), medium temperature moisture 0.10% or less (4), high temperature type 0.10% or less small make up today to explain the electric heating tube heat transfer media, magnesia performance requirements, you can study well

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